Question

What is the angle between the carbon-oxygen bonds in the carbonate (`CO_3^(2-)`) ion?

Answer 1

`/_O-C-O-=120^@`........

Explanation:

The central carbon atom is surrounded by `3xxsigma` bonds, and a `C-O` `pi` bond, that is conceived to be delocalized around the oxygen centres:

`O=C(-O)_2^(-)`

Electron counting means that we have to distribute 24 electrons around the oxygens and carbon, and this gives a trigonal plane around the central carbon.